Vibrio parahaemolyticus is a halophilic, Gram-negative, facultative anaerobic microorganism occurring in most of the estuarine waters of the world. It causes food poisoning associated with the consumption of seafoods and is the major bacterial cause of epidemic gastroenteritis in the countries where fish are eaten raw, such as Japan and Taiwan.
The conventional methods for the identification of V. parahaemolyticus are based on morphological, biochemical and physiological tests. These tests are tedious, time-consuming, cumbersome and costly. It normally takes several days to complete such tests, and thus the clearance of highly perishable foods is delayed. Therefore, a rapid and specific identification test for the suspect colonies is desirable, for example, a latex agglutination test.
Chang et al. in Chinese (Taiwan) Patent Application No. 79109870, Pat. No. NI-50873 published on 21 Aug. 1991 (1) disclosed a latex agglutination test for identification of the colonies of Vibrio. The latex agglutination test is characterized by coating the latex particles with antibodies against capsule antigens of V. parahaemolyticus wherein the antibodies were raised by immunizing rabbits with mixed capsule antigens of 13 strains of V. parahaemolyticus and the cross-reaction with the Aeromonas species was reduced by absorption of said antibodies with Aeromonas media.
However, it is found in this invention that the outer membrane proteins of V. parahaemolyticus, especially with molecular weights of 36,000 and 34,000, respectively, are highly antigenic and specific to V. parahaemolyticus. The invention provides a rapid identification of V. parahaemolyticus using the antibodies against the proteins.
The method of the invention is very simple and economical and can be completed within minutes. The invention provides a rapid identification of V. parahaemolyticus with high sensitivity and specificity, and low (less than 5%) false-negative and false-positive rates.